GUADALAJARA, Mexico, Aug. 10 -- President Obama, attending a North American summit with the leaders of Mexico and Canada, said Monday that his administration will pursue a comprehensive overhaul of the U.S. immigration system this year but that no action on legislation will happen before 2010.

Wrapping up the two-day meeting, Obama said that there needs to be "a pathway to citizenship" for millions of illegal immigrants in the United States, and that the system must be reworked to avoid tensions with Mexico. Without it, he said, Mexicans will keep crossing the border in dangerous ways and employers will continue exploiting workers.

"We can create a system in which you have . . . an orderly process for people to come in, but we're also giving an opportunity for those who are already in the United States to be able to achieve a pathway to citizenship so that they don't have to live in the shadows," Obama said during an hour-long news conference at the Cabañas Cultural Center in downtown Guadalajara. "Am I going to be able to snap my fingers and get this done? No. This is going to be difficult."

The president said he expects draft legislation and sponsors by the end of the year, but no action until 2010 because of more pressing issues, including health-care reform, energy legislation and financial regulatory changes.

"That's a pretty big stack of bills," he said.

Immigration is among the most controversial items on Obama's legislative agenda, with critics opposing what they call an amnesty for illegal workers and businesses concerned about reductions in their labor force. President George W. Bush twice attempted immigration reform during his second term, without success.

Asked about the prospects for immigration legislation in view of the blows to his administration over health care and midterm elections next year, Obama dismissed the idea that the elections would play a role, saying he would not act "on short-term political calculations."

Flanked by Mexican President Felipe Calderón and Canadian Prime Minister Stephen Harper, Obama also pledged to work with Mexico and Canada on controlling emissions that contribute to global warming and on ensuring that Mexico receives aid for its battle with drug traffickers.

"We have already seen resources transferred, equipment transferred . . . to help President Calderón in what is a very courageous effort to deal with a set of drug cartels that are not only resulting in extraordinary violence to the people of Mexico, but are also undermining institutions like the police and the judiciary system," he said, attempting to deflect criticism from Mexican officials who have complained that U.S. aid is not coming quickly enough.

Although Obama expressed confidence in the Mexican government's attempt to fight drug cartels with "law enforcement techniques," he reiterated the importance of doing so without violating human rights.

Calderón's government has been criticized by human rights organizations. More than 45,000 troops have been deployed to fight the cartels, and soldiers have been accused of killing, torture, rape and illegal detention. Since Calderón began fighting the cartels after taking office in December 2006, human rights complaints against the military have soared 600 percent, rising to 140 a month this year, according to government statistics.

The Mexican government has begun to hire the first of 9,000 federal police officers who are college-educated and will be trained by U.S., Canadian and other law enforcement agencies, White House drug czar Gil Kerlikowske said.

"I am confident that as the national police are trained, as the coordination between the military and local police officials is improved, there is going to be increased transparency and accountability, and that human rights will be observed," Obama said.

Calderón said his government is dedicated to guarding human rights.

"Obviously we have a strong commitment to protect the human rights of everybody -- the victims and even of the criminals themselves," he said. "And anyone who says the contrary certainly would have to prove this -- any case, just one case, where the proper authority has not acted in the correct way."

Calderón asserted that any soldiers or police officers who abused their power have been punished. According to Center Prodh, a human rights group in Mexico, fewer than 1 in 10 of the human rights cases tried in military court result in a conviction.

Calderón said his strategy, which includes the mass deployment of soldiers, is working. "We know that we are destroying their criminal organizations," he said. "We're hitting them hard. We're hitting at the heart of the organizations."

Obama, Calderón and Harper also showed support for Manuel Zelaya, who was ousted as Honduran president in a coup in June. The men agreed that Zelaya should be returned to power. During a visit to Mexico City last week, Zelaya complained that the Obama administration has offered only a tepid response to the coup leaders. Obama has been repeatedly criticized by Venezuelan President Hugo Chávez for not pressing harder for Zelaya's return.

"The same critics who say that the United States has not intervened enough in Honduras are the same people who say that we're always intervening, and the Yankees need to get out of Latin America," Obama said. "You can't have it both ways."

Harper agreed.

"If I were an American, I would be really fed up with this kind of hypocrisy," he said. "You know, the United States is accused of meddling except when it's accused of not meddling."

Staff writer William Branigin in Washington contributed to this report.